FIG. 1 illustrates the basic architecture of a cellular radio network in form of a UTRAN (Universal Terrestrial Radio Access Network) network, connected to the Internet 170 and a WLAN. The WLAN normally comprises at least one radio Access Point, AP, 165 connected to an Access Point Controller, APC, 162. The cellular radio network comprises a GGSN 110 connected to a SGSN 120 which in turn is connected to a RNC 130. A dual mode UT (User Terminal) 140, having both UTRAN and WLAN capability, can establish a UTRAN radio connection through it's first data port 141 with Base station Node B 150 and a WLAN radio connection through it's second data port 142 with the AP 165 of the WLAN. Node B 150 is connected to RNC 130. The WLAN may in a conventional manner be connected to the SGSN 120 or to the GGSN 110 or to the Internet 170, FIG. 1 illustrates the case wherein it is connected to the GGSN 110, possibly via an AR (Access Router) and/or an IP-network, not illustrated in FIG. 1. A data communication session can be established between the UT 140 and a communicating party connected to the Internet 170, e.g. by means of a conventional PDP (Packet Data Protocol) context session between the UT 140 and the GGSN 110, in accordance with the 3GPP standard for packet radio data services.
In case of a handover of a data session from the UTRAN transmission path to the WLAN transmission path, session data will be encrypted according to the WLAN security protocol exploiting the WLAN specific encryption algorithm and parameters. The set up of these parameters, e.g. the security keys during the AAA (Authentication, Authorization, Accounting) process, is time consuming, hindering an efficient and smooth handover of a data session from the UTRAN transmission path to the WLAN transmission path. This is particularly a problem for real time applications, such as e.g. telephone speech applications.
Different encryption standards in an integrated network require differentiated software management (installation, updates etc), which constitutes a problem regarding cost efficiency.
Another problem is that the WLAN security is generally considered rather weak, which hinders the full commercial exploitation of integrated WLAN/UTRAN networks.
Another important problem is that WLAN networks are so called pico-cell hotspot networks. This means that access points are placed at many locations with small cells which are to a large extent easily accessible. Even if the WLAN encryption between UT:s and AP:s (Access Points) over the radio link is relatively safe, there is no encryption of the data transmitted between AP:s and the fix parts of the WLAN, e.g. between AP 165 and APC 162 in FIG. 1, which of-course constitutes a security problem. This is illustrated in FIG. 1 wherein the encrypted connections in the WLAN and UTRAN routing paths are indicated with bold lines, the fact that parts of the WLAN connections not are encrypted hinders the full commercial exploitation of integrated WLAN-UTRAN networks.
None of the above identified problems are admitted by the applicant to constitute prior art.